I know this is a Portland radio blog; however, I thought this may relate to the Portland radio market with all the format changes and station flip-flops. Next week, Spokane's KGA (a 50kw station at 1510AM) and KJRB (a 5kw station at 790AM) are flip-flopping formats. KGA is currently news-talk and KJRB is currently Fox Sports. Next week, KGA becomes all sports while KJRB will become news-talk. Both stations are owned by Citidel. It seems a little strange to flip-flop with stations that have drastic power differences (5kw vs 50kw) but then in this day and age of radio, anything can happen, and does.

While this is out-of-market, there is a technical factor of AM signal coverage that applies anywhere.

Comparing daytime patterns, KJRB's 5000 watts at a low dial position has a slightly larger coverage area than KGA's 50,000 watts at the upper end of the band. The two pattens are actually very similar.
KJRB Day KGA Day

On the other hand, KJRB's night coverage is somewhat inferior with a power drop to 3800 watts and a tighter directional pattern than KGA.
KJRB Night KGA Night

...except for the fact that KGA plans to reduce power at night to make way for more signal from a north San Francisco Bay station. Now the whole thing makes perfect sense!

KGA nightime always has been real good to the west and SW. KJRB pulls the lisajoo pattern 'thing' at night and you really can't hear them to the east or west much at all. Nightime in West Spokane ( Fairchild AFB for example ) was ( when I worked their in 77') and still is a challenge to get a decent signal out of 790 in those areas. Newstalk really is a daytime affair for the most part, while sports is a totally different story.

Even with the reduction in power on KGA, their nightime pattern favors total coverage and then some for Spokane, the Spokane Valley, Coeur D'Alene and west to Ritzville, Moses Lake and even the Tri Cities. The frequencies dont make as much difference as the power and pattern does in this case.

Something else that just occured to me. Cheney , Wa is home to EWU , Eastern Washington University. Cheney is 17 miles Southwest of Spokane. Ill bet if you looked at a detail of the KJRB * nightime * pattern you might find that the west minima goes right through the neighborhood of the EWU campus ! Citadel sports radio probably has a lot to do with games at EWU. KGA's power and pattern is very favorable to Cheney, Wa. So it comes down to continuous whining : We cant here the game ! We cant hear the game ! and so now they WILL be able to hear the game !

KGA was the first radio station I ever sent a resume and aircheck too while going to college in Spokane. I didn't expect the PD to play my tape while I was sitting in his office (I was such a newbie) and even though he didn't offer me a job his feedback was worth it.

I was sweating bullets during those 15 minutes and have come to appreciate them more and more over the years.

I believe KGA was country back in those days.

Country from about 1970?? I think. Before that top 40. I used to listen to KGA on my Sears 6 tube radio in Vancouver, Wa in the 60s year round most nights when the sideband splatter from 1520-KGON/KYMN/KYXI wasnt too loud...It was an enjoyable alternative to KISN.

KGA was usually easy copy between Seattle and Longview and again from Salem to Medford very consistently after sunset till dawn along I-5.

A buddy of mine moved to Scio, Oregon in the 60s. He used to tell me that he would get sick of KGAL or KRKT and listen every night to KGA upstairs on his radio. It came in most every night, he said.

I think I've mentioned before here that when I was a kid in Seattle in the late 1960s, KGA, which was indeed top 40 at that time, placed billboards around the Puget Sound area inviting people to "Dial 15 tonight!" I've always been a bit curious why KGA thought it worth the expense to try to attract a few listeners at night from Western Washington.

who was the pd chris when you interviewed, our own ron norwood was there for awhile during its country heyday...in salem in the 60s you could tune in 1490 and easily be listening to 1510, it came in strong...

Currently at night KGA is unlistenable in Coeur D'Alene and even the northern Spokane sububurbs due to sever fading. It's all rather technical but the short story is one of their towers is too tall and send a good deal of signal almost straigth up. That bounces down close to Spokane and causes the fading. Reducing the power won't help & may even worsen it. And they don't propose to shorten that tower.

Boy that 'new' array' they built a few years ago for KGA must have been in the TANK ! Are they diplexed with another station? I havent kept up on anything since the mass exodus of the AMs from Moran prarie, on the South Hill, Spokane.

It might be that the tower is too tall to somehow accomodate another station on a lower freq ( ie: 790 KJRB?) as a diplexed array?? I am curious.

KGA is sharing space with KJRB. There's more of the diplexing info in "Towers & Such".

That explains a lot ! Why a tower is too tall when you are diplexing a 1510 with a 790. Of course the phasing is supposed to compensate for all that, if done correctly. And then when you have two directional stations that are diplexed it becomes a greater engineering challenge.